Barmah Forest virus infection

Barmah Forest virus disease is caused by an alphavirus that is spread by mosquitoes. It is found in some regions, particularly around inland waterways and coastal areas, but it is relatively rare.

Outbreaks happen from time to time and are linked to environmental conditions that encourage mosquito breeding, such as heavy rainfall, floods, high tides and moderate temperatures.

Symptoms#

Symptoms usually begin to appear between 7 and 10 days (and up to 21 days) after infection. Many people infected with the virus never develop any symptoms at all.

When symptoms do occur, they vary from person to person in type and severity, but can include:

• fever, chills and headache
• tiredness or fatigue
• a rash of variable appearance on the trunk and limbs
• muscle aches and pains
• swollen lymph nodes
• joint pain and swelling, which may affect the wrists, knees, ankles, or smaller joints such as fingers or toes

Some people, particularly children, may show no symptoms.

Most people with Barmah Forest virus disease recover completely within 6 months. Current knowledge suggests the body builds an immune response to the virus that is likely to protect you against the disease for the rest of your life. Some people may have symptoms that last longer than 6 months or that recur, but these may be due to other causes. See your doctor to confirm your diagnosis if you are concerned about ongoing symptoms.

How it spreads#

People become infected when they are bitten by a mosquito carrying the virus. It is thought that mosquitoes pick up the virus from animals that act as a natural host. Barmah Forest virus is not spread directly from one person to another.

Blood tests can show whether a person has been infected with the virus recently or in the past.

Prevention#

There is no preventive vaccine. The most effective protection against Barmah Forest virus and other mosquito-borne diseases is to avoid mosquito bites and remove mosquito breeding sites around your home and property.

To reduce your risk:

• Wear light-colored, loose-fitting clothes and covered shoes outdoors.
• Use mosquito repellents containing picaridin or DEET on all exposed skin.
• Limit outdoor activity when lots of mosquitoes are about.
• Use “knockdown” fly sprays and plug-in repellent devices indoors.
• Cover all windows, doors, vents and other entrances with insect screens.
• Sleep under insecticide-treated mosquito nets if you do not have screens on your windows, or if you are sleeping in an untreated tent or out in the open.
• Use mosquito coils in small outdoor areas where you gather to sit or eat.
• Remove stagnant water around your home by emptying pots and containers at least once a week.

Treatment#

There is no specific treatment for Barmah Forest virus infection. Your doctor can advise you on managing the symptoms.

Key points#

• Barmah Forest virus disease is caused by an alphavirus, which is spread by mosquitoes
• Symptoms usually begin to appear between 7 to 10 (up to 21) days after becoming infected
• However, many people infected with Barmah Forest virus will never develop any symptoms
• Some people may have symptoms that last longer than 6 months or recur, but these may be due to other causes
• See your doctor to check your diagnosis if you are concerned about ongoing symptoms

Where to get help#